Snap action switch having inclined guide return means



Oct. 11, 1966 R. F. WINOGROCKI SNAP ACTION SWITCH HAVING INCLINED GUIDE RETURN MEANS Filed Sept. l4, 1964 2 Sheets-Sheet 1 INVENTOR RAY F WlNOGROCKi ATTORNEYS Oct. 11, 1966 R. F. WINOGROCKI SNAP ACTION SWITCH HAVING INCLINED GUIDE RETURN MEANS 2 Sheets-Sheet 2 Filed Sept. 14, 1964 INVENTOR RAY E WINOGROCKI ATTOR N E YS United States Patent 3,278,701 SNAP ACTION SWITCH HAVING INCLINED GUIDE RETURN MEANS Ray F. Winogrocki, East Detroit, Mich., assignor to Boyne Products, Inc., Boyne City, Mich., a corporation of Michigan Filed Sept. 14, 1964, Ser. No. 396,109 12 Claims. (Cl. 200-67.)

This invention relates to an electrical switch construction and more particularly to a snap action type switch having a movable contact bridging blade which is capable of moving with a snap action from one position to another and in which the time of movement of the bladecan be controlled within extremely close tolerances.

Switches of the snap action type are commonly constructed in'such manner that a movable contact moves rapidly from one position to another, thereby minimizing the adverse effects of arcing which usually accompanies a slower operating contact. It is customary to effect rapid movement of such a contact by utilizing a resilient member which is capable of maintaining the movable contact in either of two positions and which must be stressed a predetermined amount in order to effect movement'of the movable contact from one position to the other. Heretofore, snap action switches of the general class referred to have necessitated a fairly large amount of travel of the stressing or operating means before the movable contact snaps from one position to the other, for the reason that the resiliency of the member to be stressed must be taken up completely before the movable contact can be snapped to its other position. In other words, snap action switches of the kind in use heretofore have had considerable mechanical hysteresis, a characteristic which is inherent in a construction in which the snap action is obtained by stressing a flexible contact or contact support.

There are many instances in which it would be desirable to utilize a snap action switch and in which hysteresis in one direction of movement of the movable contact is not objectionable, but in which the same amount of hysteresis in the other direction of movement cannot be tolerated. In other instances, however, any large degree of hysteresis in either direction of movement of the movable contact is undesirable.

An object of this invention is to provide a snap action switch construction having a movable contact which may be snapped from one position to another, and returned, and in which mechanical hysteresis is relatively small.

Another object of the invention is to provide a snap action switch in which the movable contact does not rely for its movement upon the stressing of a resilient contact member.

Another object of the invention is to provide a snap action switch of the character referred to and which is adaptable to a number of different kinds of actuating devices.

A further object of the invention is to provide a snap action switch in which a movable contact may be shifted manually from one position to another and returned to its first position automatically.

Another object of the invention is to provide a snap action switch which is composed of relatively few parts, thereby facilitating assembly and minimizing the risk of failure.

Other objects and advantages of the invention will be pointed out specifically or will become apparent from the following description when it is considered in conjunction with the appended claims and the accompanying drawings, in which:

FIGURE 1 is a top plan view of a switch constructed in accordance with one embodiment of the invention, cer- Patented Oct. 11, 1966 tain parts being broken away for purposes of clarity;

FIGURE 2 is an enlarged, transverse sectional view taken on the line 22 of FIGURE 1;

FIGURE 3 is a longitudinal sectional view of a switch constructed in accordance with another embodiment of the invention, the section being taken on the line 3-3 of FIGURE 4; and

FIGURE 4 is a sectional view taken on the line 4--4 of FIGURE 3.

A switch constructed in accordance with the embodiment of the invention disclosed in FIGURES 1 and 2 is designated by the reference character 1 and comprises a casing 2 formed of insulating material and having a number of wings 3 or the like provided with openings 4 for the reception of screws (not shown) or the like by means of which the casing may be secured to a suitable supporting structure 5. The casing member 2 comprises a supporting wall 6 surrounded by an upstanding, annular wall 7 providing a hollow cavity 8. A snap-on cover 9 may be provided to close the casing 2.

Within the cavity 8 is secured a mounted member or bracket 10 comprising an electrically conductive base 11 fitted into a recess formed in the cavity wall 6 and secured thereto by a conductive contact or rivet 12 which extends through the wall 6 and to which one end of a conductor 13 is connected. In the disclosed embodiment a second contact or rivet 14 extends through the Wall 6 and has connected thereto one end of a conductor 15. The conductors 13 and 15 emerge from the casing 2 through an opening provided therein and may be con nected respectively to a source of energy and to an electrically operated device.

The mounting member 10 includes a pair of spaced apart, parallel, upstanding arms 16 that are integrally formed with the base 11. At one side of each arm is a notch 18. The opposite side of each arm is provided with a smooth, flat, inclined guide surface 19. As is best illustrated in FIGURE 2, the guide surfaces 19 overhang the base 11 a substantial distance.

The switch 1 includes a substantially rigid blade 20 formed of electrically conductive material and having a planar body portion 21 one end of which is adapted to engage the contact 14. At its other end the body portion 21 is notched at its opposite sides to provide terminal ends 22 and a pair of flanges 23. The terminal ends 22 of the body member 21 are received in the notches 18 and the flanges 23 are received between the arms 16. In these positions of the parts the blade 20 is capable of pivoting or rocking movement in a clockwise direction about the fulcrum provided by the notches 18 from the full line position shown in FIGURE 1. Preferably, the cover 9 is provided with a depending rib 24 so as to limit clockwise movement of the blade 20.

In the embodiment of the invention disclosed in FIGURES 1 and 2 of the drawings, the switch includes an operating member 26 comprising a generally cylindrical body 27 terminating at its opposite ends in cylindrical extensions 28. The length of the body member 27 is such as to enable it to be accommodated between the arms 16 of the mounting member 10, and the length of the extensions 28 is such as to enable them to project beyond the arms 16 and engage the guide surfaces 19 on the latter. The operating member 26 is reciprocable along the guide surfaces 19.

Means designated generally by the reference character 30 is provided for interconnecting the blade 20 and the operating member 26 and for effecting rocking move- 'ments of the blade in response to movements of the operating member. The interconnecting means 30 comprises a tension spring 31 having a hook 32 at one end that is received in an opening 33 formed in the blade body 21 and having a similar book 34 at its other end that iis accommodated in an annular groove 35 formed in the body 27. The overall length of the spring 31 is such that,

when its opposite ends are connected to the respective members and 26, the spring is stressed in tension so .as to exert a force on the members 20 and 26 tending to urge them toward one another. The rigidity of the blade 20 enables substantial force to be applied by the spring without deformation of the blade. As a result, the blade body 21 is snugly retained in the fulcrum notches 18 and the operating member 26 is snugly retained in engagement with the guide surfaces 19.

Actuating means 37 is provided for effecting movements of the operating member 26. The actuating means comprises an internally threaded shaft 38 that is rotatably received in an opening 39 formed in the support 5, the shaft 38 accommodating a correspondingly threaded screw 40 having a multisided head 41 that is slideably but nonrotatably accommodated in an opening 42 provided in the base 6. The arrangement is such that rotation of the shaft 38 in one direction will effect movement of the screw 40 in a direction to cause engagement between the head 41 and the body 27 of the actuating member 26 and move the latter from the position shown in full lines in FIGURE 2 to the position shown in dotted lines. Rotation of the shaft 38 in the opposite direction will cause the screw 40 to be retracted into the shaft.

In the position of the parts shown in full lines in FIG- URE 2, the force of the spring 31 is transmitted from the member 26 to the member 20 along a straight line which passes below the fulcrum 18. Consequently, the spring 31, being under tension, yieldably maintains the blade 20 in engagement with the contact 14. In this position of the blade, a circuit may be completed from the contact 14 through the body member 21, through the arms 16, through the base 11 to the contact 12.

Rotation of the shaft 38 in such direction as to effect movement of the operating member 26 to the dotted line first will effect engagement between the head 41 and the actuating member 26. As the shaft 38 is rotated the bolt head 31 will exert a force on the operating member 26 urging the latter to move in such direction that the latter moves from its first position on one side of the plane of the blade 20 to a second position on the other side of the plane of the blade. The line of force reacting between the blade 20 and the operating member 26 thus will be transferred from one side of the plane of the blade to the other and, as the line of force is transferred, the blade 20 will pivot accordingly. Thus, as the body member 26 moves from the full line position toward the dotted line position shown in FIGURE 2, the blade body 21 will be pivoted about the fulcrum 18 from the full line position to the dotted line position, thereby breaking the circuit between the contacts 12 and 14. I

When the body member 26 is in the position shown in dotted lines in FIGURE 2, it will have traversed the inclined guide surface 19 of the mounting member 10, thereby imposing additional stress on the spring 31. As a result of the stressing of the spring 31, coupled with the inclination of the guide surfaces 19, the body member 26 constantly is urged in a return direction toward the full line position. Consequently, rotation of the shaft 38 in such direction as to retract the bolt 40 into the shaft will enable the operating member 26 to be restored automatically to its first or normal position.

To avoid interference between the spring 31 and the blade body 21, the latter is provided with a slot 46. To limit the movement of the operating member 26 under the influence of the spring 31, the wall 6 of the casing 2 may be provided with a pair of parallel, upstanding ribs 47 on which the extensions 28 may rest.

From the foregoing, it will be apparent that the spring 31 not only maintains the blade 20 and the operating member 26 in assembled relation with the mounting member 10, but also functions to effect restoration of the switch blade 20 from the dotted line position shown in FIGURE 2 to the full line position. An important characteristic of the invention, however, is that movement of the switch blade 20 from one of its positions to the other does not depend upon stressing of the blade or of the spring 31. Instead, movement of the switch blade depends solely upon shifting of the line of force reacting between the blade 20 and the operating member 26 from one side of the plane of the blade to the other. As a result, the amount of movement which must be imparted to the operating member 26 to effect shifting of the blade 20 can be precisely determined and, accordingly, the mechanical hysteresis characteristics of the switch may be controlled to a point not heretofore possible in switches of thesnap action type.

The embodiment of the invention disclosed in FIG- URES 3 and 4 is similar in many respects to the previous ly described embodiment, but is illustrative of various modifications of which the switch is susceptible. In the embodiment shown in FIGURES 3 and 4 a casing 50 is composed of two halves 51 and 52 formed of nonconductive material which may be maintained in assembled relation by rivets 53 extending through ears 54 provided on the respective sections. The interior of the casing 50 is divided by a partition 55 into two compartments 56 and 57.

Within the compartment 56 is a mounting member 58 formed of electrically conductive material and comprising a base 59 which is secured to the base 60 of the compartment 56 by an electrically conductive contact rivet 61 which also anchors one end of a conductive member 62 to the casing. The base 59 is flanked by a pair of upstanding, parallel, spaced apart arms 63, each of which is provided at one side with a fulcrum-forming notch 64 and at the other side with an inclined guide surface 65 which terminates adjacent the base 59 in a vertical surface 66. Except for the vertical surface 66, the mounting member 58 is similar to the mounting member 10 previously described.

Spaced from the contact rivet 61 is a similar contact rivet 67 which projects through the base wall 60 of the casing 50 and anchors one end of an electrically conductive member 68. Aligned with, but spaced from, the contact 67 is a similar contact rivet 69 which extends through the casing half 51 and anchors one end of an electrically conductive member 70.

Interposed between the contacts 67 and 69 within the casing 50 is an electrically conductive, substantially rigid blade 71 having a substantially planar body member 72 similar'to the previously described body 21. Preferably, the body member 72 is provided with a pair of opposed contacts 73 that are adapted to engage the contacts 67 and 69.

Spaced from the blade 71 and on the opposite side of the mounting member 58 is an operating member 74 that is similar in all respects to the operating member 26. The member 74 has a body 75 terminating at opposite ends in cylindrical extensions 76 which are adapted to bear against the guide surfaces 6 5 on the arms 63. A tension spring 77 is interposed between the arms 63 and has one end 78 received in an opening 79 provided in the blade body 72 and has its other end 80 accommodated in an annular groove 81 formed in the body 75. The arrangement is such that the spring 77 urges the members 71 and 74 toward one another and into snug engagement with the opposite sides of the mounting member 58 in the same manner previously described in connection with the embodiment shown in FIGURES 1 and 2. The operating member 74 is capable of being moved bodily from the full line position shown in FIGURE 3 to the dotted line position, whereulp the line of force exerted on the members 71 and 74 by the spring 77 will shift from one side of the plane of the blade body 72 to the other and effect clockwise rocking of the blade 71 about the fulcrum 64 so as to disengage the contacts 73 and 67 and engage the contacts 73 and 69. l

Act-uating means for effecting movements of the operating member 74 is designated generally by the reference character 82 and comprises a plunger stem 83 which is reciprocably mounted in the partition 55 for movements toward and away from the operating member 74. One end of the plunger stem 83 is provided with a wedgeshaped head 84 which is received in the compartment 56 and which is adapted to pass between the base 60 of the casing and the body 75. A compression spring 86 surrounds the stem 83 and reacts between the partition 55 and an enlargement 87 on the stem. so as normally to urge the stem and the head 84 in a direction away from the operating member 74. i v Ifdesired, the free end of the plunger stem may project through the casing 50 for engagement with any kind of forceapplying means. In the disclosed embodiment, however, the free end of the plunger stem .terminates within the casing 50 and is received within a cup-shaped member 88 having a radially extending flange 89 provided with circumferentially spaced, axially extending grooves adapted to receive circumferentially spaced ribs 90 provided on the inner surface of the casing 50. The flange 89 also is provided with a plurality of circumferentially spaced, angular teeth 91 that are adapted to be engaged by complementally shaped teeth 92 provided at one end of a tubular plunger 93 having a stem 94 which projects through an opening in the casing 50. Between the member 88 and the plunger 93 is'a light compression spring 95. The arrangement is such that movement of the plunger 93 to the left, as is viewed in FIGURE 3, will effect corresponding movement of the member 88 until such time as the grooves in the flange 89 clear the teeth 90. Thereupon, the angular teeth' 91 and 92 on'the members 88 and 93, respectively, will act to rotate the member 88 to a position in which the ribs 90 are misaligned with the grooves in the flange 89. The member 88, therefore, will be maintained in its adjusted position in the same manner that the point of a conventional ballpoint pen is maintained in its projected position.

Movement of the member 88 axially to the left, as is viewed in FIGURE 3, will cause corresponding movement of the plunger 83 and the head 84, thereby shifting the operating member 74 laterally from its full line position to its dotted line position and effecting snap action of the blade 71 into engagement with the contact 69. In these positions of the parts, the force of the spring 77 exerted on the members 71 and 74 will be along the line which is above the fulcrum 64. Consequently, the spring 31 will tend to urge the contact 73 into snug engagement with the contact 69, thereby completing a circuit between the contacts 61 and 69. The rigidity of the blade enables considerable force to be exerted by the spring without fear of distorting the blade.

When it is desired to return the blade 71 to the position shown in FIGURE 3, the stem '94 may be depressed, or moved to the left, so as to effect rocking of the member 88 by the interaction of the teeth 91 and 92. Such rocking will realign the ribs 90 with the grooves in the flange 89, thereby enabling the spring 86 to move the stem 83 to the right upon release of the member 94. Movement of the stem 83 to the right will cause corresponding movement of the head 84, thereby enabling the spring 77, in cooperation with the guide surfaces 65, to return the operating member 74 to the full line position shown in FIG- URE 3. In this position of the operating member, the force exerted by the spring 77 on the members 71 and 74 is along a line which is located below the fulcrum 64, thereby enabling the spring to hold the blade 71 in engagement with the contact 67 and enabling a circuit to be completed between the contacts 67 and 61. As the operating member moves from either of its positions toward the other, the shifting of the line of force exerted on the members 71 and 74 from one side of the fulcrum to the other will effect a snap action of the blade.

The disclosed embodiments are representative of presently preferred forms of the invention, but are intended to be illustrative rather than definitive thereof. The invention is defined in the claims.

I claim:

1. A snap action switch comprising a casing; an upstanding mounting member supported on said casing; means at one side of said mounting member forming a fulcrum; means at the opposite side of said mounting member forming an inclined guide; a substantially planar blade rockably mounted at said fulcrum; an operating member in reciprocable engagement with and guided by said guide for movements transversely of and through the plane of said blade; resilient means connected at its opposite end to said blade and to said operating member respectively and forcibly urging said blade and said operating member into engagement with the respective sides of said mounting member, the force exerted by said resilient means being along a straight line from its connections to said blade and to said operating member; and actuating means sup ported by said casing and operable to effect movement of said operating member from a first position in which the line of force of said resilient means moves from one side of said plane to the other side thereof and effects rocking of said blade about said fulcrum, said guide being inclined to the plane of said blade in such direction that said resilient means constantly exerts a force on said operating member urging the latter toward said first position.

2. The construction set forth in claim 1 wherein said operating member is rotatable.

' 3. The construction set forth in claim 1 wherein said actuating means includes a rotatable part.

4. The construction set forth in claim 3 wherein said actuating means includes a linearly movable part connected to and operated by said rotatable part.

5. The construction set forth in claim 1 wherein said actuating means includes a linearly reciprocable member.

6. The construction set forth in claim 5 including yieldable means acting on said linearly reciprocable part and urging the latter in one direction of movement.

7. A snap action switch comprising a casing; an upstanding mounting member supported on said casing; means at one side of said mounting member forming a fulcrum; a substantially planar blade rockably mounted at said fulcrum; means at the opposite side of said mounting member forming a guide inclined transversely to the plane of said blade; an operating member reciprocably guided by said guide for movements transversely of the plane of said blade from a first position at one side of said plane to a second position at the other side of said plane; spring means connected at its opposite ends and under tension to said blade and to said operating member respectively and forcibly urging said blade and said operating member into engagement with the respective sides of said mounting member, the force exerted by said spring means being along a straight line from its connections to said blade and to said operating member; and actuating means supported by said casing and operable to effect movement of said operating member from a first position in which the line of force of said spring means is at one side of said fulcrum to a second position in which the line of force is at the other side of said fulcrum, the movement of said line of force from its first position to its second position effecting rocking of said blade about said fulcrum, the inclination of said guide being such that the force exerted by said spring means constantly urges said operating member to move along said guide toward its said first position.

8. A switch of the snap action or the like type comprising a blade having a substantially planar portion; a pair of substantially parallel, spaced apart mounting members having means at corresponding sides thereof forming a fulcrum against which one end of said blade is rockably engaged, the opposite corresponding sides of said mounting members being inclined to the plane of said blade; an operating member in engagement with and spanning the inclined sides-of said mounting members; spring means interposed between said mounting members and connected at its opposite ends to said blade and to said operating member, respectively, said spring means exerting on said blade and said operating member a straight line force of such magnitude as to maintain the blade and the mounting member constantly in engagement with the respective sides of said mounting members and to urge said operating member to a first position at one side of the plane of said blade; actuating means; and means movably mounting said actuating means for engagement with said operating member for moving the latter from said first position to a second position on the other side of the plane of said blade, movement of said operating member to said second position causing the line of force exerted by said spring means on said blade and on said operating member to shift from said one side of the plane of said blade to the opposite side of the plane of said blade and effect rocking movement of said blade about said fulcrum.

9. A switch of the snap action type comprising a blade having a substantially planar portion; means mounting said blade for rocking movements of said portion about a fulcrum from a first position on one side of said fulcrum to a second position on the other side of said fulblade for moving the latter from one of said positions to the other in response to movement of said operating means from one side of the plane of said blade portion to the other, said force transmitting means cooperating with said guide means to exert a force on said operating actuating means engageable with said operating means for effecting movement of the latter; and means mounting said actuating means for reciprocating movements substantially parallel to said plane.

12. The construction set forth in claim 9 wherein said force transmitting means comprises a spring connected 'under tension to said operating means andto said blade.

References Cited by the Examiner UNITED STATES PATENTS 1,224,652 5/ 1917 Kocourek. 2,596,893 5/ 1952 Finizie. 3,049,600 8/ 1962 Fraser. 3,157,759 11/1964 Kudalis.

ROBERT K. SCHAEFER, Primary Examiner.

KATHLEEN H. CLAFFY, Examiner.

D. SMITH, JR., Assistant Examiner. 

1. A SNAP ACTION SWITCHING COMPRISING A CASING; AN UPSTANDING MOUNTING MEMBER SUPPORTED ON SAID CASING MEANS AT ONE SIDE OF SAID MOUNTING MEMBER FORMING A FULCRUM; MEANS AT THE OPPOSITE SIDE OF SAID MOUNTING MEMBER FORMING AN INCLINED GUIDE; A SUBSTANTIALLY PLANAR BLADE ROCKABLY MOUNTED AT SAID FULCRUM; AN OPERATING MEMBER IN RECIPROCABLE ENGAGEMENT WITH AND GUIDED BY SAID GUIDE FOR MOVEMENTS TRANSVERSELY OF AND THROUGH THE PLANE OF SAID BLADE; RESILIENT MEANS CONNECTED AT ITS OPPOSITE END TO SAID BLADE AND TO SAID OPERATING MEMBER RESPECTIVELY AND FORCIBLY URGING SAID BLADE AND SAID OPERATING MEMBER INTO ENGAGEMENT WITH THE RESPECTIVE SIDES OF SAID MOUNTING MEMBER, THE FORCE EXERTED BY SAID RESILIENT MEANS BEING ALONG A STRAIGHT LINE FROM ITS CONNECTIONS TO SAID BLADE AND TO SAID OPERATING MEMBER; AND ACTUATING MEANS SUPPORTED BY SAID CASING AND OPERABLE TO EFFECT MOVEMENT OF SAID OPERATING MEMBER FROM A FIRST POSITION IN WHICH THE LINE OF FORCE OF SAID RESILIENT MEANS MOVES FROM ONE SIDE OF SAID PLANE TO THE OTHER SIDE THEREOF AND EFFECTS ROCKING OF SAID BLADE ABOUT SAID FULCRUM, SAID GUIDE BEING INCLINED TO THE PLANE OF SAID BLADE IN SUCH DIRECTION THAT SAID RESILIENT MEANS CONSTANTLY EXERTS A FORCE ON SAID OPERATING MEMBER URGING THE LATTER TOWARD SAID FIRST POSITION. 